Diet and nutrition have a key influence on our health. We also know, that nutrition and other influences from our lifestyles or environment, affect health and disease risk in concert with our individual genetic make-up. Due to recent advances in gene discovery, it is now possible to examine the joint effects of genes and environment. Importantly, this will help to establish how by making changes where we can (e.g. diet, lifestyle), we can ameliorate adverse influences caused by susceptibility genes which we cannot alter.
The Nutritional and Genetic Epidemiology Group (NGEG) utilises tools from observational and genetic epidemiology to investigate the role of nutrition in public health. NGEG investigates gene-environment interactions, and uses genetic markers in causal modelling. Work under the theme includes projects examining intergenerational and genetic influences on growth and disease risk, as well as short and long term health effects of vitamin D, coffee consumption, obesity and other lifestyle factors. Much of the work is done using large scale population data collections, in part in the context of large scale international collaborations.
The group is led by Professor Elina Hyppönen, Director for the Centre for Population Health Research. NGEG is based at the South Australian Health and Medical Research Institute (SAHMRI).
Lifestyle and health: examining gene-environment interactions and cause-effect relationships
While randomised clinical trials are the gold standard for testing causal effects, they are not always feasible or ethical to conduct and can be very expensive. An alternative approach used by the NGEG is “Mendelian Randomisation” (MR), where genetic markers are used as proxy indicators for lifestyle (or other) exposures. MR can provide evidence about causal effects by avoiding reverse causality and by reducing the unexplained confounding – both common concerns with traditional observational studies.
Combined with methods of observational nutritional epidemiology, research by NGEG utilises genetic factors
- to examine the cause-effect association between lifestyle factors and health outcomes
- to obtain insights into pathways mediating the effect of nutrition on health
- to examine possible safety concerns associated with the use of dietary supplements
Examples for ongoing projects
- Vitamin D deficiency is prevalent in adults, and it has been suggested to contribute to the development of cardiovascular diseases, diabetes, mood disorders, cognitive decline and eventually, mortality risk. However, causality for many of the observed associations has not been demonstrated, with much of the evidence arising from observational studies potentially affected by confounding and reverse causality. Professor Hyppönen leads the international D-CarDia collaboration focused on establishing the causality and safety of vitamin D and calcium in relation to cardiovascular risk. Currently D-CarDia consists of over 40 studies from all around the world with over 150,000 individuals in aggregate.
- The effects of our lifestyle behaviours on cognitive function remain poorly understood and there is no effective prevention for dementia. With recent funding from the Mason-Williams foundation, NGEG is working to establish effective dietary approaches to prevent cognitive decline and reduce dementia risk. This work is led by Professor Hyppönen, and includes in aggregate over 100,000 participants from various studies around the world.
- Smoking behaviour is associated with the likelihood of obesity and also poor mental health - areas where potential reverse causality can confuse interpretation. As part of the so-called CARTA Consortium (“Causal Analyses Research on Tobacco and Alcohol”) NGEG is working to establish the direction of related cause-effect associations.
Research Degree Supervisor
Professor Hyppönen conducts research on how genes and environment work in concert to affect our health and disease risk, working with various large cohort studies and international collaborations. Her areas of expertise range from life-course and intergenerational epidemiology to medical statistics, genetic association studies and public health nutrition. She has a strong ethos for training and mentoring the next generation of professionals and leaders in epidemiology. Opportunities within NGEG include various types of multidisciplinary projects, commonly providing opportunities to collaborate with leading investigators around the world.